Try some powers of two arithmetic to get a feel for how many ancestors you have in a particular generation 2300 years ago (the time of Aaron) or even a mere 1000 years ago. If 25 years per generation is a fair guess, then 40 generations ago in 1000AD would give you one trillion grandparents for that single generation. The population of Europe in 1000AD is estimated at only 36 million. Those of European blood are probably a direct descendent of every single European alive then who has living decendents today. And not in one branch of the tree, but thousands of times over on average.

Taking it back 2300 years (world population est. <27M), we're all very likely direct decendents of Aaron, regardless of race or religion, billions of times over.